The British government has launched a review of arms exports to Bahrain after it emerged that the country's security forces were supplied with weapons by the United Kingdom.

After a bloody crackdown in the capital, Manama, left up to five people dead and more than 100 injured, Foreign Office minister Alistair Burt said the government will "urgently revoke licences if we judge that they are no longer in line with the [UK and European Union] criteria".

Despite long-running concerns among activists over Bahrain's human rights record, British firms were last year granted licences, unopposed, to export an arsenal of sometimes deadly crowd control weapons. Licences approved included exactly the kind of weapons and ammunition used by Bahraini riot police to clear the Pearl Roundabout protest encampment, including shotguns, teargas canisters, "crowd control ammunition" and stun grenades.

"We closely consider allegations of human rights abuses," said Burt. "We will not authorise any exports which, we assess, might provoke or prolong regional or internal conflicts, which might be used to facilitate internal repression."

Human rights groups called for an immediate suspension of arms supplies to Bahrain and the disclosure of why licences were granted in the first place.

Last night, the Ministry of Defence was unable to say what role the British military has supporting or advising the Bahraini defence forces through secondments or training programmes. Military analysts said the anglophile nature of the Bahraini elite made it likely. "The Bahrain military employs a number of British citizens as advisers on organisation and strategy in the ministry of interior and the ministry of defence," said Jonathan Eyal, the director of international security studies at the Royal United Services Institute.

According to the Foreign Office's own records and the Campaign Against the Arms Trade, the UK has also supplied Libya – which has warned in an SMS message that it will use live ammunition against protesters – with similar weapons and ammunition. Sales to both Bahrain and Libya were actively promoted by the UK government's arms promotion unit, the UK Trade & Investment Defence & Security Organisation.

Despite the widespread unrest throughout the Middle East and North Africa, British arms manufacturers this weekend will be attending IDEX, a major arms fair in Abu Dhabi, to promote sales throughout the Middle East region.

Examination by the Guardian of pictures of the injuries of the dead and injured taken at hospitals in Bahrain showed the tell-tale blast pattern of shotgun pellets, including on a young, seriously injured child who appeared to have been shot in the ribcage at close range. Credible witnesses to both Thursday's assault and a similar attack on a funeral procession in Manama describe police using shotguns, alleged to have been responsible for the death of mourner Fadhel Ali Almatrook.

Other licences granted for export to Bahrain by the UK included small arms ammunition and submachine guns.

Despite the warnings from HRW and other organisations of a worsening rights situation in Bahrain, the Foreign Office's own statistics reveal that the number of arms exports licences continued to increase in 2010 from 34 to 42 with no licences being refused. Arms exports to Libya, where lethal force has already been used against demonstrators, appear to have followed a similar pattern with exports last year including tear gas, and £3.2 million worth of ammunition including for crowd control..

Denis MacShane, a former Labour minister, said: "We should be suspending all arms exports used to repress pro-democracy protests. The idea that British weapons could be used to fire on and injure children makes me feel ill."